In automatic toll systems, a license number identification which is based on optical pattern recognition or “Optical Character Recognition” OCR for short, is frequently used in the course of monitoring correct payment of the toll fees and for identification of toll infringes, with a high probability of identification normally being required. The performance of OCR is highly dependent on the environmental conditions (weather), and requires either a high degree of local computation power or a large amount of data to a central OCR host.
In some toll systems, the toll fees are paid continuously by communication with the toll infrastructure or via devices which are similar to repayment cards. In the first case, the identity of the vehicle is not known in the latter. In both cases, however, correct payment of the toll fees must be monitored, and potential toll infringes must be identified.
One system of the type mentioned initially is described, for example, in WO 99/66455. In this case, an apparatus for monitoring the correct operation of a toll payment apparatus is arranged at the side of the road, with the toll payment apparatus being arranged in a vehicle that is passing the apparatus and has a license plate, and with communication taking place between the toll appliance and the apparatus. If, on the basis of the communication with the toll payment apparatus, the apparatus identifies that the toll payment apparatus is not being operated correctly, then the license plate of the vehicle is recorded by way of a recording device.
However, this apparatus has the disadvantage that a communication link must be set up between the toll appliance and the apparatus, for which reason the production of this apparatus is associated with high costs.